Qualite et vitesse de decomposition des litieres des principaux arbustes natifs de la savane humide au centre de la Cote d’Ivoire

Cette étude a été conduite en zone de savane humide de Côte d’Ivoire pour évaluer la qualité et la vitesse de décomposition des litières de feuilles de trois espèces d’arbustes dominantes: Crossopteryx febrifuga, Terminalia schimperiana et Piliostigma thonningii et la contribution des termites dans ce processus. La vitesse de décomposition a été suivie pendant six mois dans des sachets (Litterbags) puis le coefficient de décomposition k a été déterminé. La contribution des termites a été estimée à travers la quantité de sol « termitique » déposée sur les sachets. Les résultats montrent que les teneurs des litières en C, N, K et Mg étaient plus élevés avec C. febrifuga qu’avec P. thonningii et T. schimperiana respectivement. Le rapport N/P suivait exactement la même tendance. La teneur en P n’a pas varié significativement avec les espèces. Les rapports C/N et C/P n’ont pas non plus varié significativement. La concentration de Ca des litières était plus élevée avec P. thonningii. La densité surfacique des litières (caractéristique physique) était plus élevée avec P. thonningii qu’avec les autres espèces. La décomposition des litières de T. schimperiana (0,64 mois-1) était plus rapide que celles de C. febribuga (0,52 mois-1) et de P. thonningii (0,39 mois-1). L’activité des termites était plus importante sous les litières les plus denses (P. thonningii). L’espèce C. febrifuga est apparue comme ayant le meilleur potentiel d’amélioration de la fertilité du sol.   English title: Quality and decomposition rate of native shrub species’ leaf litters in a wet savanna in central Côte d’Ivoire This study was conducted in Central Côte d’Ivoire, aimed to assess the quality and rate of decomposition of the dominant native shrub species’ leaf litters, namely Crossopteryx febrifuga, Terminalia schimperiana and Piliostigma thonningii and the termite’s contribution in this process. Investigations took place in the Lamto Natural Reserve, including five replicate trees per species. Leaf litters were left to decompose in litterbags for six months and then, the decomposition coefficient (k) was determined. The termites’ contribution to decomposition was estimated by the amount of soil they deposited on the litterbags. Results showed that higher leaf litter C, N, K and Mg concentrations were associated with C. febrifuga compared to P. thonningii and T. schimperiana, respectively. The N/P ratio followed the same order. Litter P, C/N and C/P ratios did not varied across species. Higher litter Ca was observed with P. thonningii. Litter surface area was higher with P. thonningii compared to the other two species while decomposition was faster with T. schimperiana (k = 0.64 month-1) followed by C. febribuga (k = 0.52 month-1) and P. thonningii (0.39 months-1). The contribution of the termites to decomposition were found to be greater on high surface area-leaf litters, supposedly more ligneous (P. thonningii). These results suggest that C. febrifuga holds a greater ability to improve soil fertility

Caractérisation phénotypique et génétique du riz africain (Oryza glaberrima Steud) phenotypic and genetic characterization of african rice (oryza glaberrima steud)

The agronomic interest of African rice and the morphological similarities with other species, arouse the necessity to characterize African rice for recovery and conservation. The present study aims primarily to characterize phenotypically and genetically African rice for better exploitation in aid of rice producers and consumers. Indeed, the phenotypic characteristics of the rice accessions examined have been determined in two agronomics systems (upland and irrigated) carried out about 235 accessions of African rice; and afterwards, genetic characterization using a specific marker has been carried. At the end of the analyzes, with regard to the phenotypic characters, 22 O.sativa or interspecific accessions differing morphologically on several descriptors were identified. Genetically, out of 19 profiles revealed on a 935-bp band, 14 confirmed the phenotypic results. This study shows that 221 out of 235 accessions are O. glaberrima rice. These results show that the accessions of different species analyzed were confused during the collection. They also seems to validate the possibility of hybridization between the two rice species in peasant environment. The accessions characterized strengthen the conservation effort of African rice. This collection can be used for future studies, particularly with perspective to selection and running African rice with the possibility to establish a genetic model to facilitate the transfer of useful genes from O.glaberrima to O.sativa, while controlling the reproductive barrier. Thus, it will be easy to better exploit the genetic diversity of the African species of cultivated rice

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Determinants de l’adoption des semences certifiees de varietes ameliorees du riz au Benin

Au Bénin, la diffusion des variétés à haut rendement de riz s’est accélérée en réponse à une demande croissante de cette denrée. Ces variétés évaluées par la recherche, favorisent l’augmentation du rendement de la production rizicole. Pour cela, la semence de ces variétés nécessite un renouvellement périodique dans les structures garantissant la certification. De ce fait, il existe une différence entre les riziculteurs qui utilisent les semences non certifiées des variétés améliorées et ceux qui utilisent des semences certifiées des variétés améliorées. Malheureusement, cette différentiation n’est pas prise en compte dans la plupart des études de l’adoption des variétés à haut rendement. Cette étude prend alors en compte cet aspect en explicitant les déterminants de l’adoption et de l’intensité d’adoption des semences certifiées des variétés améliorées. Les données ont été collectées auprès d’un échantillon aléatoire de 272 ménages agricoles au Bénin. Les modèles Probit et Tobit sont respectivement utilisés pour identifier les variables affectant l’adoption et de l’intensité d’adoption des semences certifiées des variétés améliorées. Les résultats montrent que 81% des variétés utilisées sont améliorées et 19% sont des variétés traditionnelles. Parmi les adoptants des variétés améliorées, 37% utilisent des semences certifiées. Malgré un faible taux d’adoption des semences certifiées, l’intensité moyenne d’utilisation est de 30%. Les résultats montrent que l’appartenance à une association, le type de crédit, l’activité secondaire et la quantité d’engrais chimiques influencent l’adoption des semences certifiées au niveau des riziculteurs. Par ailleurs, les variables telles que la superficie agricole, l’activité secondaire et le sexe sont décisives sur l’intensité d’adoption. Les résultats suggèrent que pour accroître le taux d’adoption des semences certifiées, les octrois de crédit et les sensibilisations des riziculteurs à travers les associations sont recommandés.Mots clés: Adoption, semence certifiée, riz, déterminants, tobit, probitEnglish Title: Determinants of adoption of certified seeds of improved rice varieties in BeninEnglish AbstractIn Benin, the dissemination of high yield varieties of rice increased in response to the growing demand for this crop. These varieties assessed by the research favor the increase of rice yield. To this end, the seed of these varieties requires a periodical renewal in the structures guarantying the certification. From this fact, there exists in one hand, rice producers who use non certified seeds of the improved varieties and on the other hands, those who use certified seeds of these varieties. Unfortunately, this differentiation is not  taken into account in the adoption studies on seeds of high yield varieties. This study takes into account this aspect in clarifying the adoption determinants as well as the certified seeds adoption intensity. The data were collected from a random sample of 272 farming households. Probit and Logit models are respectively used to identify the variables that affect the adoption and the intensity of adoption of the certified seeds of the improved varieties. The results show that 81% of the varieties used are improved while 19% are traditional varieties. Among the adopters of the improved seeds, 37% use certified seeds. Despite this low percentage of adoption of certified seeds, the mean intensity of use of certified seeds is 30%. The results reveal that being member of a cooperative, the type of credit, the off-rice production activity and the quantity of chemical inputs influence adoption of certified seeds of the improved varieties. Moreover, the variables such as farm lands area, the off-rice production activities and gender are decisive on the adoption intensity. Therefore, in order to increase the certified seeds adoption rate, credit supply and the rice farmers’ awareness through the cooperatives are recommended.Keywords: adoption, certified Seeds, rice, determinants, tobit, probi

Changes in soil pH, polyphenol content and microbial community mediated by Eucalyptus camaldulensis

Eucalyptus camaldulensis has been the main exotic species planted in reforestation programs in the tropics due to its fast growth and adaptability to climate variations. Based on the premise that the conversion from natural grazed pastures to commercial Eucalyptus plantations generates significant changes in soil properties, we assessed the impact of this exotic plantation on soil chemical and biological indicators. The study was conducted in 6 plantations across Senegal following a decreasing rainfall gradient from south to north. The plantations were divided in three lots according to their age: young plantations (established in 2003, 6 years old); intermediate plantations (established in 1998, 11 years old) and old plantations (established in 1982 and 1983, 26 years old). Our results clearly showed that E. camaldulensis plants significantly modified soil pH and soil bacterial community at all sites regardless of the age of the plantation. Microbial biomass (assessed by substrate-induced respiration), community structure (assessed by denaturing gradient gel electrophoresis profiles) and function (assessed by Catabolic Response Profile using different substrates) were all significantly decreased. The acidifying effect of E. camaldulensis, the effect of high level of polyphenols and their impact on microbial communities and ecosystem functioning were discussed